| /* |
| * Copyright 2022 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package androidx.compose.ui.node |
| |
| import androidx.compose.foundation.layout.Box |
| import androidx.compose.runtime.getValue |
| import androidx.compose.runtime.mutableStateOf |
| import androidx.compose.runtime.setValue |
| import androidx.compose.ui.ExperimentalComposeUiApi |
| import androidx.compose.ui.Modifier |
| import androidx.compose.ui.test.junit4.createComposeRule |
| import androidx.test.ext.junit.runners.AndroidJUnit4 |
| import androidx.test.filters.MediumTest |
| import com.google.common.truth.Truth.assertThat |
| import org.junit.Rule |
| import org.junit.Test |
| import org.junit.runner.RunWith |
| |
| @OptIn(ExperimentalComposeUiApi::class) |
| @MediumTest |
| @RunWith(AndroidJUnit4::class) |
| class ObserverNodeTest { |
| @get:Rule |
| val rule = createComposeRule() |
| |
| @Test |
| fun simplyObservingValue_doesNotTriggerCallback() { |
| // Arrange. |
| val value by mutableStateOf(1) |
| var callbackInvoked = false |
| val observerNode = TestObserverNode { callbackInvoked = true } |
| rule.setContent { |
| Box(Modifier.modifierElementOf(observerNode)) |
| } |
| |
| // Act. |
| rule.runOnIdle { |
| // Read value to observe changes. |
| observerNode.observeReads { value.toString() } |
| } |
| |
| // Assert. |
| rule.runOnIdle { |
| assertThat(callbackInvoked).isFalse() |
| } |
| } |
| |
| @Test |
| fun changeInObservedValue_triggersCallback() { |
| // Arrange. |
| var value by mutableStateOf(1) |
| var callbackInvoked = false |
| val observerNode = TestObserverNode { callbackInvoked = true } |
| rule.setContent { |
| Box(Modifier.modifierElementOf(observerNode)) |
| } |
| |
| // Act. |
| rule.runOnIdle { |
| // Read value to observe changes. |
| observerNode.observeReads { value.toString() } |
| |
| // Write to the read value to trigger onObservedReadsChanged. |
| value = 3 |
| } |
| |
| // Assert. |
| rule.runOnIdle { |
| assertThat(callbackInvoked).isTrue() |
| } |
| } |
| |
| @Test(expected = IllegalStateException::class) |
| fun unusedNodeDoesNotObserve() { |
| // Arrange. |
| var value by mutableStateOf(1) |
| var callbackInvoked = false |
| val observerNode = TestObserverNode { callbackInvoked = true } |
| |
| // Act. |
| rule.runOnIdle { |
| // Read value to observe changes. |
| observerNode.observeReads { value.toString() } |
| |
| // Write to the read value to trigger onObservedReadsChanged. |
| value = 3 |
| } |
| |
| // Assert. |
| rule.runOnIdle { |
| assertThat(callbackInvoked).isFalse() |
| } |
| } |
| |
| @Test |
| fun detachedNodeCanObserveReads() { |
| // Arrange. |
| var value by mutableStateOf(1) |
| var callbackInvoked = false |
| val observerNode = TestObserverNode { callbackInvoked = true } |
| var attached by mutableStateOf(true) |
| rule.setContent { |
| Box(if (attached) Modifier.modifierElementOf(observerNode) else Modifier) |
| } |
| |
| // Act. |
| // Read value while not attached. |
| rule.runOnIdle { attached = false } |
| rule.runOnIdle { observerNode.observeReads { value.toString() } } |
| rule.runOnIdle { attached = true } |
| // Write to the read value to trigger onObservedReadsChanged. |
| rule.runOnIdle { value = 3 } |
| |
| // Assert. |
| rule.runOnIdle { |
| assertThat(callbackInvoked).isTrue() |
| } |
| } |
| |
| @Test |
| fun detachedNodeDoesNotCallOnObservedReadsChanged() { |
| // Arrange. |
| var value by mutableStateOf(1) |
| var callbackInvoked = false |
| val observerNode = TestObserverNode { callbackInvoked = true } |
| var attached by mutableStateOf(true) |
| rule.setContent { |
| Box(if (attached) Modifier.modifierElementOf(observerNode) else Modifier) |
| } |
| |
| // Act. |
| rule.runOnIdle { |
| // Read value to observe changes. |
| observerNode.observeReads { value.toString() } |
| } |
| |
| rule.runOnIdle { |
| attached = false |
| } |
| // Write to the read value to trigger onObservedReadsChanged. |
| rule.runOnIdle { value = 3 } |
| |
| // Assert. |
| rule.runOnIdle { |
| assertThat(callbackInvoked).isFalse() |
| } |
| } |
| |
| @ExperimentalComposeUiApi |
| private inline fun <reified T : Modifier.Node> Modifier.modifierElementOf(node: T): Modifier { |
| return this.then(modifierElementOf(create = { node }, definitions = { name = "testNode" })) |
| } |
| |
| class TestObserverNode( |
| private val onObserveReadsChanged: () -> Unit, |
| ) : ObserverNode, Modifier.Node() { |
| override fun onObservedReadsChanged() { |
| this.onObserveReadsChanged() |
| } |
| } |
| } |